Optical recording medium

ABSTRACT

An optical recording medium is disclosed, comprising a support having provided thereon a recording layer containing a naphtholactam dye represented by formula: ##STR1## wherein K represents a substituted or unsubstituted aromatic amine residue; R represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted allyl group; Z -  represents an anion; ring A represents a substituted or unsubstituted naphthalene ring; and m represents 1 or 2. The recording layer can be formed by coating easily, has a high reflectance to provide a satisfactory contrast of recording, and exhibits excellent resistance to light.

FIELD OF THE INVENTION

This invention relates to an optical recording medium. More particularly, it relates to an optical recording medium whose recording layer has a high reflectance and can be formed easily.

BACKGROUND OF THE INVENTION

Optical recording media using a laser beam, etc. including laser discs are capable of recording and preserving informations at high densities and reproducing the recorded informations easily.

Laser discs generally comprise a disc base having provided thereon a thin recording layer, on which a laser beam condensed to a diameter of about 1 μm is irradiated to carry out high-density recording. Upon absorption of energy of the irradiated laser beams, the recording layer undergoes thermal changes, such as decomposition, evaporation, dissolution, and the like to thereby make a difference in reflectance between the irradiated areas and the non-irradiated areas. Reproduction of the recorded informations can be carried out by reading the difference of reflectance.

Therefore, in order to effect high-density recording and precise reproduction, optical recording media are required to show efficient absorption of a laser beam having a specific wavelength used for recording and to highly reflect a laser beam having a specific wavelength used for reproduction.

Various structures are known for this type of optical recording media. For example, Japanese Patent Application (OPI) No. 97033/80 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") discloses a support having provided thereon a single layer of phthalocyanine dyes. However, phthalocyanine dyes have disadvantages, such as low sensitivity, high decomposition points which lead to difficulty in vacuum deposition, and very low solubility in organic solvents which lead to difficulty in coating for formation of the recording layer.

Japanese Patent Application (OPI) Nos. 83344/83 and 22479/83 disclose phenalene dyes and naphthoquinone dyes, respectively, to be coated as a recording layer. These dyes, though easy to evaporate in vacuo, show low reflectances. Low reflectances result in poor contrast in reflectance between the recorded areas and non-recorded areas, thus making it difficult to reproduce the recorded informations.

In addition, Japanese Patent Application (OPI) Nos. 24692/84, 67092/84, and 71895/84 disclose recording layers comprising cyanine dyes. The cyanine dyes have an advantage of easy coating but are inferior in light resistance and undergo deterioration due to light for reproduction.

SUMMARY OF THE INVENTION

One object of this invention is to provide an optical recording medium whose recording layer can be formed by coating easily.

Another object of this invention is to provide an optical recording medium whose recording layer has a high reflectance to provide a satisfactory contrast of recording.

A further object of this invention is to provide an optical recording medium having excellent resistance to light, particularly light for reproduction.

As a result of extensive investigations, it has now been found that the above objects can be accomplished easily by providing a recording layer containing a naphtholactam light-absorbing dye having a specific chemical structure.

The present invention relates to an optical recording medium comprising a support having provided thereon a recording layer containing a naphthostyril light-absorbing dye represented by formula (I): ##STR2## wherein K represents a substituted or unsubstituted aromatic amine residue; R represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted allyl group; Z⁻ represents an anion; ring A represents a substituted or unsubstituted naphthalene ring; and m represents 1 or 2.

DETAILED DESCRIPTION OF THE INVENTION

In formula (I), substituents for the alkyl, cycloalkyl, aryl or allyl group as represented by R include an alkoxy group, an alkoxyalkoxy group, an alkoxyalkoxyalkoxy group, an allyloxy group, an aryl group, an aryloxy group, a cyano group, a hydroxyl group, a tetrahydrofuryl group, a halogen atom, etc.

Substituents for the naphthalene ring as represented by ring A include a halogen atom, a cyano group, a thiocyanate group, an alkyl group having up to 10 carbon atoms, an alkoxy group having up to 10 carbon atoms, an alkylamino group, an acylamino group, an amino group, a hydroxyl group, and a like nonionic substituent.

The substituted or unsubstituted aromatic amine residue as represented by K include residual groups of heterocyclic amines containing a nitrogen atom, an oxygen atom or a sulfur atom, residual groups of tetrahydroquinolines, and groups represented by formula: ##STR3##

wherein X and Y each represents a hydrogen atom, an alkyl group, an acylamino group, an alkoxy group, or a halogen atom; and R² and R³ each represents a hydrogen atom, a substituted or unsubstituted alkyl group having up to 20 carbon atoms, a substituted or unsubstituted aryl group, a substituted or unsubstituted allyl group, or a substituted or unsubstituted cycloalkyl group.

Substituted for the alkyl, aryl, allyl or cycloalkyl group as represented by R² or R³ include an alkoxy group, an alkoxyalkoxy group, an alkoxyalkoxyalkoxy group, an allyloxy group, an aryl group, an aryloxy group, a cyano group, a hydroxyl group, a tetrahydrofuryl group, etc.

Anions represented by Z⁻ include I⁻, Br⁻, Cl⁻, ClO₄ ⁻, BF₄ ⁻, SCN⁻, ##STR4##

The naphtholactam dyes represented by formula (I) absorbs light in the wavelength region of from 600 to 900 nm and have a molecular absorption coefficient of from 10⁴ to 10⁵ cm⁻¹.

Among the naphtholactam dyes of formula (I), the preferred are those represented by formula (II): ##STR5## wherein X and Y each represents a hydrogen atom, a halogen atom, an alkyl group, an acylamino group, or an alkoxy group; R¹ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted allyl group; R² and R³ each represents a hydrogen atom, a substituted or unsubstituted alkyl group having up to 20 carbon atoms, a substituted or unsubstituted aryl group, a substituted or unsubstituted allyl group, or a substituted or unsubstituted cycloalkyl group; R⁴ and R⁵ each represents a hydrogen atom, a halogen atom, a cyano group, a thiocyanato group, an alkyl group having up to 10 carbon atoms, an alkoxy group having up to 10 carbon atoms, an alkylamino group, an acylamino group, an amino group, or a hydroxyl group; Z⁻ represents an anion; and m represents 1 or 2.

In formula (II), substituents for the alkyl, aryl, allyl, or cycloalkyl group as represented by R² or R³ include an alkoxy group, an alkoxyalkoxy group, an allyloxy group, an aryl group, an aryloxy group, a cyano group, a hydroxyl group, a tetrahydrofurfuryl group, a halogen atom, etc.

The more preferred of the naphthostyril dyes of formula (II) are those represented by formula (III): ##STR6## wherein X represents a hydrogen atom or a methyl group; R¹ represents an alkyl group having up to 8 carbon atoms, and preferably up to 5 carbon atoms, an alkyl group having up to 8 carbon atoms, and preferably up to 5 carbon atoms, which is substituted with an alkoxy group, preferably the one having up to 4 carbon atoms, an allyloxy group or a hydroxyl group, or an allyl group; R² and R³ each represents an alkyl group having up to 8 carbon atoms, an alkyl group having up to 8 carbon atoms which is substituted with an alkoxy group, preferably the one having up to 4 carbon atoms, an alkoxyalkoxy group, preferably the one having up to 4 carbon atoms, an allyloxy group, a hydroxyl group or a halogen atom, or an allyl group; R⁴ represents a hydrogen atom, a halogen atom, preferably a chlorine atom or a bromine atom, or a thiocyanate group; Z⁻ represents an anion; and m represents 1 or 2.

The naphthostyril dyes represented by formula (II) can easily be prepared by condensing a compound represented by formula: ##STR7## wherein R¹, R⁴, R⁵, and Z⁻ are as defined for formula (II), with an aromatic aldehyde represented by formula: ##STR8## wherein X, Y, R², R³, and m are as defined in formula (II).

The naphthostyril dyes of formula (II) can also be prepared by reacting a compound represented by formula: ##STR9## wherein R¹, R², R³, R⁴, R⁵, X, Y, and m are as defined above; and Z⁻ represents I⁻, Br⁻, Cl⁻, ClO₄ ⁻, BF₄ ⁻, SCN⁻, PF₆ ⁻, SiF₆ ⁻, TiF₆ ⁻, ##STR10## with a compound represented by formula:

    Q.sup.-.X.sup.+

wherein Q represents ##STR11## and X⁺ represents a tetraalkylammonium cation, etc., in a polar solvent under heating with stirring.

The optical recording medium according to the present invention essentially comprises a support and a recording layer and, if desired, may further comprise a subbing layer on the support and a protective layer on the recording layer.

The support to be used may be either transparent or opaque to a laser beam used. Any of supports usually employed for this type of recording media, such as glass, plastics, paper, metal plates or foils, etc., may be used, with plastics being preferred from various respects. The plastics to be used include acrylic resins, methacrylic resins, vinyl acetate resins, vinyl chloride resins, nitrocellulose, polyethylene resins, polypropylene resins, polycarbonate resins, polyimide resins, polysulfone resins, and the like.

The recording layer of the optical recording medium of the invention has a thickness of from 100 Å to 5 μm, and preferably from 500 Å to 3 μm.

The recording layer can be formed by a commonly employed thin film formation techniques, such as a vacuum deposition process, a sputtering process, a doctor blade coating process, a casting process, a spinner coating process, a dip coating process, and the like.

In the formation of the recording layer, a binder may be simultaneously used in a naphthostyril type light absorbing dyes. Usable binders include polymers, such as polyvinyl alcohol, polyvinylpyrrolidone, nitrocellulose, cellulose acetate, polyvinyl butyral, polycarbonate, etc. The recording layer preferably contains at least 1% by weight of the naphthostyril dye based on the polymer binder.

In the case of coating the recording layer by the above-described doctor blade coating process, casting process, spinner coating process, dip coating process, and the like, and particularly spinner coating process, a solvent for coating is employed. Suitable solvents to be used include those having a boiling point of from 120° to 160° C., e.g., bromoform, dibromoethane, tetrachloroethane, ethyl cellosolve, xylene, chlorobenzene, cyclohexanone, etc. In the case of film formation by the spinner coating process, a rotational speed preferably ranges from 500 to 5,000 rpm, and the spin-coated layer may be heated or treated with a solvent vapor, if necessary.

For the purpose of ensuring stability or light resistance of the recording layer, the recording layer may contain, as a singlet state oxygen quencher, a transition metal chelate compound, e.g., acetylacetonato chelates, bisphenyldithiol, salicylaldehyde oxime chelates, bisdithiol-α-diketone, etc.

The recording layer according to the present invention may further contain other dyes in addition to the naphthostyril dyes of formula (I), such as naphthostyril dyes other than those of the present invention, indophenol dyes, triarylmethane dyes, azo dyes, cyanine dyes, squalilium dyes, etc.

The recording layer of the optical recording medium according to the present invention may be provided on either a single side or both sides of a support.

Recording on the optical recording medium of the invention can be performed by irradiating the recording layer provided on one or both sides of the support with a laser beam, and preferably a semiconductor laser beam, condensed to a diameter of about 1 μm. The laser irradiation induces thermal deformation of the recording layer due to energy absorption, such as decomposition, evaporation, melting, and the like, to thereby effect recording.

Reproduction of the thus recorded information can be carried out by irradiating a laser beam to read a difference in reflectance between the area where such a thermal deformation has taken place and the area where no thermal deformation has taken place.

The laser beams which can be used for recording and reproduction include laser beams of N₂, He--Cd, Ar, He--Ne, ruby, semiconductors, dyes, and the like. Of these, semiconductor laser beams are preferred in view of their lightweight, small size, and ease on handling.

This invention will now be illustrated in greater detail with reference to the following examples, but it should be understood that they are not intended to limit the present invention.

EXAMPLE 1 Synthesis of Naphthostyril Dye

To a mixture of 250 g of glacial acetic acid and 50 g of acetic anhydride were added 39.0 g of a compound of formula: ##STR12## and 19.1 g of a compound of formula: ##STR13## and the mixture was heated at 100° to 105° C. for 4 hours with stirring. After completion of the reaction, the reaction mixture was cooled to room temperature, and poured into 1.5 liters of water containing 16.0 g of sodium perchlorate, followed by stirring at room temperature for 8 hours. The formed crystals were collected by filtration and dried to obtain 45 g of a naphthostyril dye having the following formula as a dark green crystals. A chloroform solution of this dye showed a λ_(max) of 740 nm. ##STR14##

Production of Optical Recording Medium

One gram of the naphthostyril dye as above prepared was dissolved in ethyl cellosolve, followed by filtration through a filter of 0.22 μm, 2 ml of thus obtained solution was dropped on a substrate of polycarbonate resin disc having a diameter of 130 mm which had been grooved to a depth of 700 Å and a width of 0.7 μm, and coated by a spinner at 800 rpm, followed by drying at 60° C. for 20 minutes. For film thickness measurement, a glass plate was separately coated with the coating solution under the same conditions as above, and the film thickness was measured by means of Talystep (Rank Taylor Hobson KK) and was found to be 650 Å. The coated film exhibited its absorption maximum at a wavelength of 790 nm and a broad peak width.

When a semiconductor laser beam having a center wavelength of 830 nm and a beam diameter of 1 μm was irradiated on the coated film at an output of 6 mW, clear-outlined pits having a width of about 1 μm and a pit length of about 2 μm were formed. The carrier level/noise level ratio (C/N ratio) of the pits was 52 dB. The coating film exhibited satisfactory light resistance and resistance to reproducing light.

EXAMPLE 2

A naphthostyril dye of the formula shown below was synthesized in the same manner as described in Example 1. A chloroform solution of the dye had a λ_(max) of 740 nm. ##STR15##

One gram of the naphthostyril dye thus obtained was dissolved in 50 g of dibromoethane, followed by filtration through a filter of 0.22 μm. 2 ml of the resulting solution was dropped on a substrate of methyl methacrylate resin (hereinafter referred to as PMMA) disc having a diameter of 120 mm which had been grooved to a depth of 700 Å and a width of 0.7 μm and coated by a spinner at 1200 rpm, followed by drying at 60° C. for 10 minutes. The film thickness was measured in the same manner as in Example 1 and was found to be 700 Å. The coating film showed its absorption maximum at 790 nm with a broad peak width.

When a semiconductor laser beam having a center wavelength of 830 nm and a beam diameter of about 1 μm was irradiated on the coated film at an output of 6 mW, clear-outlined pits having a width of about 1 μm and a pit length of about 2 μm were formed. The C/N ratio of the pits was 48 dB. The coating film showed satisfactory light resistance and resistance to reproducing light.

EXAMPLE 3 Synthesis of Naphthostyril Dye

To 50 ml of N,N-dimethylformamide were added 6.48 g of a dye having formula: ##STR16## and 6.20 g of a compound of formula: ##STR17## and the mixture was heated at 90° to 100° C. for 3 hours. After cooling, the reaction mixture was poured into 300 ml of water, and the mixture was stirred at room temperature for 1 hour. The thus precipitated crystals were collected by filtration and dried to obtain 10.20 g of dark green crystals represented by the formula shown below. A chloroform solution of the product had a λ_(max) of 745 nm. ##STR18##

Production of Optical Recording Medium

One gram of the naphthostyril dye as above prepared was dissolved in 50 g of tetrachloroethane, and the solution was filtered through a filter of 0.2 μm. 2 ml of the resulting solution was dropped on a substrate of PMMA disc having a diameter of 130 mm which had been grooved to a depth of 700 Å and a width of 0.7 μm and coated thereon by a spinner at 800 rpm, followed by drying at 60° C. for 20 minutes. The film thickness was measured in the same manner as in Example 1 and was found to be 700 Å. The coated film exhibited its absorption maximum at 790 nm with a broad peak width.

When a semiconductor laser beam having a center wavelength of 830 nm and a beam diameter of 1 μm was irradiated on the coated film at an output of 6 mW, clear-outlined pits having a width of about 1 μm and a pit length of about 2 μm were formed. The C/N ratio of the pits was 52 dB. The coated film exhibited satisfactory light resistance and resistance to reproducing light.

EXAMPLES 4 TO 95

In the same manner as described in Example 1, naphthostyril dyes shown in Table 1 were synthesized. The wavelength of the absorption maximum of each of the resulting dye in its chloroform solution was as shown in Table 1.

Each of the resulting dyes was coated on a substrate of grooved polycarbonate resin disc in the same manner as in Example 1. The wavelength of the absorption maximum of the coating film was as shown in Table 1.

When a semiconductor laser beam having a center wavelength of 830 nm was irradiated on the coated film, clearly outlined pits were formed. The thus formed recording layer had a high reflectance, high sensitivity, and an excellent C/N ratio, and exhibited satisfactory light resistance and resistance to reproducing light.

    TABLE 1       Naphthostyril Dye       ##STR19##                  λ max λ max Example          (in CHCl.sub.3)      (coating film) No. R A.sup.1 A.sup.2 A.sup.3 B.sup.1 B.sup.2 B.sup.3 K      Z.sup.- (nm) (nm)                    4 C.sub.2       H.sub.5 H H H H H H      ##STR20##       I.sup.- 740 790       5 " " " Br " " "      ##STR21##       ClO.sub.4.sup.- 735 780       6 " " " " " " "      ##STR22##       " 745 790       7 " " " " " " "      ##STR23##       " 745 785       8 " " " " " " "      ##STR24##       " 745 790       9 " " " " " " "      ##STR25##       " 740 780       10 " " " " " " "      ##STR26##       " 735 775       11 " " " " " " "      ##STR27##       " 730 770       12 " " " " " " "      ##STR28##       " 735 780       13 " " " " " " "      ##STR29##       " 735 780       14 " " " " " " "      ##STR30##       " 720 760       15 " " " " " " "      ##STR31##       " 740 780       16 " " " " " " "      ##STR32##       " 735 775       17 " " " " " " "      ##STR33##       " 735 775       18 " " " " " " "      ##STR34##       " 725 765       19 " " " " " " "      ##STR35##       " 740 780       20 " " " " " " "      ##STR36##       " 735 775       21 " " " " " " "      ##STR37##       " 740 780       22 " " " " " " "      ##STR38##       " 735 775       23 " " " " " " "      ##STR39##       " 765 800       24 " " " " " " "      ##STR40##       " 780 820       25 " " " " " " "      ##STR41##       " 760 800       26 " " " " " " "      ##STR42##       I.sup.- 800 845       27 " " " " " " "      ##STR43##       " 770 815       28 " " " " " " "      ##STR44##       " 715 755       29 " " " " " " "      ##STR45##       " 725 760       30 " " " " " " "      ##STR46##       " 735 770       31 " " " " " " "      ##STR47##       " 735 755       32 " " " " " " "      ##STR48##       " 735 775       33 " " " " " " "      ##STR49##       Br.sup. - 735 770       34 " " " " " " "      ##STR50##       " 735 770       35 " " " " " " "      ##STR51##       " 750 790       36 " " " " " " "      ##STR52##       " 740 780       37 " " " " " " "      ##STR53##       " 745 785       38 " " " " " "  "      ##STR54##       " 745 785       39 " " " " " " "      ##STR55##       " 760 800       40 " " " " " " "      ##STR56##       BF.sub.4.sup.- 755 795  41 C.sub.3 H.sub.7       (n) " " " " " "      ##STR57##       " 740 780  42 C.sub.5 H.sub.11 (n) " " " " " " " " 740 780       43      ##STR58##       " " " " " " " " 745 780       44      ##STR59##       " " " " " " " " 745 785  45 C.sub.2 H.sub.4 OCH.sub.3 " " " " " " " "      740 780 45 CH.sub.2 CH.sub.2 CH.sub.2 OCH.sub.3 " " " " " " " " 740 780      46       ##STR60##       " " " " " " "       ##STR61##       740 780       48      ##STR62##       " " " " " " " " 740 790  49 C.sub.2 H.sub.4 OC.sub.2 H.sub.4 OCH.sub.3      " " " " " "  " " 740 790 50 C.sub.2 H.sub.4 OC.sub.2 H.sub.4 OC.sub.2      H.sub.4 OCH.sub.3 " " " " " " " " 740 790 51 C.sub.2 H.sub.4 OCH.sub.2   C      CHH.sub.2 " " " " " " " " 740 785 52 CH.sub.2 CHCH.sub.2 " " " " " " " "      745 785       53      ##STR63##       " " " " " " " " 740 790  54 C.sub.2 H.sub.4 OCH.sub.2 CHCH.sub.2 " " "      " " " " ClO.sub.4.sup.- 740 780 55 C.sub.2 H.sub.4 OH " " " " " " " "      740 780 56 C.sub.2 H.sub.4 Cl " " " " " " "  SCN.sup.- 745 785  57       ##STR64##       " " " " " " " " 740 770  58 C.sub.2 H.sub.4 CN " " " " " " " " 745 780      59 " " " H " " " " " 740 775       60 " " "      ##STR65##       " " " "  " 780 820       61 " " " H " " "      ##STR66##       ClO.sub.4.sup.- 745 760       62 " " "  " " " "      ##STR67##       " 745 785  63 C.sub.2       H.sub.5 " "      ##STR68##       " " "       ##STR69##       ##STR70##       740 780       64 " " " Cl " " "      ##STR71##       ##STR72##       740 770       65 " Br " Br " " " "      ##STR73##       745 775  66 " H " OCH.sub.3 " " " "  " 750 790  67 " " " NHCH.sub.3 " "      " " " 760 795       68 " " " Br " " "      ##STR74##       ClO.sub.4.sup.- 760 790       69 " " " " " " "      ##STR75##       " 780 810       70 " " " " " " "      ##STR76##       " 760 800       71 " " " " " " "      ##STR77##       " 785 815       72 " " " " " " "      ##STR78##       " 785 810       73 " " " " " " "      ##STR79##       " 770 800       74 " " " " " " "      ##STR80##       " 740 790       75 " " " " " " "      ##STR81##       " 755 790       76 " " " " " " "      ##STR82##       " 775 805       77 " " " OH " " "      ##STR83##       " 755 795       78 " " " NH.sub.2 " " "      ##STR84##       " 775 810  79 " " "  NHC.sub.2       H.sub.5 " " "      ##STR85##       " 775 805       80 " " " NHCOCH.sub.3 " " "      ##STR86##       " 755 800       81 " " "      ##STR87##       " " "       ##STR88##       " 740 770       82 " " " Br " " "      ##STR89##       " 750 780       83 " Br " " " " "      ##STR90##       " 780 820       84 " " " " " " "      ##STR91##       " 750 770       85 " " " " " " Br      ##STR92##       " 775 800       86 " " " CH.sub.3 " " "      ##STR93##       " 775 805  87 " " " C.sub.2 H.sub.5 "  " C.sub.2       H.sub.5      ##STR94##       " 755 790       88 " H " H H " H      ##STR95##       " 740 780       89 " " " SCN " " "      ##STR96##       SCN.sup.- 748 780       90 " " " " " " "      ##STR97##       " 745 770       91 " " " " " " "      ##STR98##       " 740 765       92 " " " Br " " "      ##STR99##       " 747 780  93 " " " " " " " " PF.sub.6.sup.- 748 780 94 " " " " " " " "      SiF.sub.6.sup.- 750 780 95 " " " " " " " " TiF.sub.6.sup.- 750 780

EXAMPLES 96 TO 184

In the same manner as described in Example 3, naphthostyril dyes shown in Table 2 were synthesized. Each of the resulting naphtolactam dyes was coated on a substrate of grooved PMMA disc in the same manner as in Example 1 to form a coated film. The wavelength of the maximum absorption of the coated film was shown in Table 2.

When a laser beam having a center wavelength of 830 nm was irradiated on the coated film, clear-outlined pits were formed. The coated film had a high reflectance, high sensitivity, and an excellent C/N ratio and exhibited satisfactory light resistance and resistance to reproducing light.

    TABLE 2       Naphthostyril Dye       ##STR100##                  λ max           (coating Example          film) No. R A      .sup.1 A.sup.2 A.sup.3 B.sup.1 B.sup.2 B.sup.3 K Z.sup.- (nm)                    96 C.sub.2       H.sub.5 H H Br H H H      ##STR101##       ##STR102##       740   97 C.sub.2 H.sub.4       CN H H H H H H      ##STR103##       ##STR104##       740   98 C.sub.2       H.sub.5 H H Br H H H      ##STR105##       ##STR106##       780   99 C.sub.2       H.sub.5 H H Br H H H      ##STR107##       ##STR108##       790  100 C.sub.2       H.sub.5 H H Br H H H      ##STR109##       ##STR110##       785  101 C.sub.2       H.sub.5 H H Br H H H      ##STR111##       ##STR112##       790  102 C.sub.2       H.sub.5 H H Br H H H      ##STR113##       ##STR114##       780  103 C.sub.2       H.sub.5 H H Br H H H      ##STR115##       ##STR116##       775  104 C.sub.2       H.sub.5 H H Br H H H      ##STR117##       ##STR118##       770  105 C.sub.2       H.sub.5 H H Br H H H      ##STR119##       ##STR120##       780       106 C.sub.2 H.sub.5 H H Br H H H      ##STR121##       ##STR122##       780  107 C.sub.2       H.sub.5 H H Br H H H      ##STR123##       ##STR124##       760  108 C.sub.2       H.sub.5 H H Br H H H      ##STR125##       ##STR126##       780  109 C.sub.2       H.sub.5 H H Br H H H      ##STR127##       ##STR128##       775  110 C.sub.2       H.sub.5 H H Br H H H      ##STR129##       ##STR130##       775  111 C.sub.2       H.sub.5 H H Br H H H      ##STR131##       ##STR132##       765  112 C.sub.2       H.sub.5 H H Br H H H      ##STR133##       ##STR134##       780  113 C.sub.2       H.sub.5 H  H Br H H H      ##STR135##       ##STR136##       775  114 C.sub.2       H.sub.5 H H Br H H H      ##STR137##       ##STR138##       780  115 C.sub.2       H.sub.5 H H Br H H H      ##STR139##       ##STR140##       775  116 C.sub.2       H.sub.5 H H Br H H H      ##STR141##       ##STR142##       800  117 C.sub.2       H.sub.5 H H Br H H H      ##STR143##       ##STR144##       820  118 C.sub.2       H.sub.5 H H Br H H H      ##STR145##       ##STR146##       800  119 C.sub.2       H.sub.5 H H Br H H H      ##STR147##       ##STR148##       845   120 C.sub.2       H.sub.5 H H Br H H H      ##STR149##       ##STR150##       815  121 C.sub.2       H.sub.5 H H Br H H H      ##STR151##       ##STR152##       755  122 C.sub.2       H.sub.5 H H Br H H H      ##STR153##       ##STR154##       760  123 C.sub.2       H.sub.5 H H Br H H H      ##STR155##       ##STR156##       770  124 C.sub.2       H.sub.5 H H Br H H H      ##STR157##       ##STR158##       755  125 C.sub.2       H.sub.5 H H Br H H H      ##STR159##       ##STR160##       775  126 C.sub.2       H.sub.5 H H Br H H H      ##STR161##       ##STR162##       770  127 C.sub.2       H.sub.5 H H  Br H H H      ##STR163##       ##STR164##       770  128 C.sub.2       H.sub.5 H H Br H H H      ##STR165##       ##STR166##       790  129 C.sub.2       H.sub.5 H H Br H H H      ##STR167##       ##STR168##       780  130 C.sub.2       H.sub.5 H H Br H H H      ##STR169##       ##STR170##       785  131 C.sub.2       H.sub.5 H H Br H H H      ##STR171##       ##STR172##       785  132 C.sub.2       H.sub. 5 H H Br H H H      ##STR173##       ##STR174##       800  133 C.sub.2       H.sub.5 H H Br H H H      ##STR175##       ##STR176##       795  134 C.sub.3 H.sub.7       (n) H H Br H H H      ##STR177##       ##STR178##       780  135 C.sub.5 H.sub.11       (n) H H Br H H H      ##STR179##       ##STR180##       780       136      ##STR181##       H H Br H H H       ##STR182##       ##STR183##       780       137      ##STR184##        H H Br H H H       ##STR185##       ##STR186##       785  138 C.sub.2 H.sub.4       OCH.sub.3 H H Br H H H      ##STR187##       ##STR188##       780  139 CH.sub.2 CH.sub.2 CH.sub.2       OCH.sub.3 H H Br H  H H      ##STR189##       ##STR190##       775       140      ##STR191##       H H Br H H H       ##STR192##       ##STR193##       780       141      ##STR194##       H H Br H H H       ##STR195##       ##STR196##       790  142 C.sub.2 H.sub.4 OC.sub.2 H.sub.4 OCH.sub.3 H H Br H H H       ##STR197##       ##STR198##       790  143 C.sub.2 H.sub.4 (OC.sub.2 H.sub.4).sub.2 OCH.sub.3 H H Br H H      H       ##STR199##       ##STR200##       790  144 C.sub.2 H.sub.4 OCH.sub.2       CHCH.sub.2 H H Br H H H      ##STR201##       ##STR202##       785  145 CH.sub.2       CHCH.sub.2 H H Br H H H      ##STR203##       ##STR204##       785       146      ##STR205##       H H Br H  H H       ##STR206##       ##STR207##       790  147 C.sub.2 H.sub.4 OCH.sub.2       CHCH.sub.2 H H Br H H H      ##STR208##       ##STR209##       780  148 C.sub.2 H.sub.4       OH H H Br H H H      ##STR210##       ##STR211##       780  149 C.sub.2 H.sub.4       Cl H H Br H H H      ##STR212##       ##STR213##       785       150      ##STR214##       H H Br H H H       ##STR215##       ##STR216##       770  151 C.sub.2 H.sub.4       CN H H Br H H H      ##STR217##       ##STR218##       775  152 C.sub.2 H.sub.4       CN H H H H H H      ##STR219##       ##STR220##       780  153 C.sub.2 H.sub.4       CN H H      ##STR221##       H H H       ##STR222##       ##STR223##       820  154 C.sub.2 H.sub.4       CN H H H H H H      ##STR224##       ##STR225##       760  155 C.sub.2 H.sub.4       CN H H H H H H      ##STR226##       ##STR227##       785   156 C.sub.2       H.sub.5 H H      ##STR228##       H H H       ##STR229##       ##STR230##       780  157 C.sub.2       H.sub.5 H H Cl H H H      ##STR231##       ##STR232##       770  158 C.sub.2       H.sub.5 Br H Br H H H      ##STR233##       ##STR234##       775  159 C.sub.2       H.sub.5 H H OCH.sub.3 H H H      ##STR235##       ##STR236##       790  160 C.sub.2       H.sub.5 H H NHCH.sub.3 H H H      ##STR237##       ##STR238##       795  161 C.sub.2       H.sub.5 H H Br H H H      ##STR239##       ##STR240##       790  162 C.sub.2       H.sub.5 H H Br H H H      ##STR241##       ##STR242##       810  163 C.sub.2       H.sub.5 H H Br H H H      ##STR243##       ##STR244##       800  164 C.sub.2       H.sub.5 H H Br H H H      ##STR245##       ##STR246##       815  165 C.sub.2       H.sub. 5 H H Br H H H      ##STR247##       ##STR248##       810  166 C.sub.2       H.sub.5 H H Br H H H      ##STR249##       ##STR250##       800  167 C.sub.2       H.sub.5 H H Br H H H      ##STR251##       ##STR252##       790  168 C.sub.2       H.sub.5 H H Br H H H      ##STR253##       ##STR254##       790  169 C.sub.2       H.sub.5 H H Br H H H      ##STR255##       ##STR256##       805  170 C.sub.2       H.sub.5 H H OH H H H      ##STR257##       ##STR258##       795  171 C.sub.2       H.sub.5 H H NH.sub.2 H H H      ##STR259##       ##STR260##       810  172 C.sub.2 H.sub.5 H H NHC.sub.2       H.sub.5 H H H      ##STR261##       ##STR262##       805  173 C.sub.2       H.sub.5 H H NHCOCH.sub.3 H H H      ##STR263##       ##STR264##       800  174 C.sub.2       H.sub.5 H H      ##STR265##       H H H       ##STR266##       ##STR267##       770  175 C.sub.2       H.sub.5 H H Br H H H      ##STR268##       ##STR269##       780  176 C.sub.2       H.sub.5 Br H Br H H H      ##STR270##       ##STR271##       820  177 C.sub.2       H.sub.5 Br H Br Br H H      ##STR272##       ##STR273##       770  178 C.sub.2       H.sub.5 Br H Br Br H Br      ##STR274##       ##STR275##       800  179 C.sub.2       H.sub.5 Br H CH.sub.3 Br H Br      ##STR276##       ##STR277##       805  180 C.sub.2 H.sub.5 Br H C.sub.2 H.sub.5 Br H C.sub.2 H.sub.5       ##STR278##       ##STR279##       790  181 C.sub.2       H.sub.5 H H H H H H      ##STR280##       ##STR281##       780  182 C.sub.2       H.sub.5 Br H SCN H H H      ##STR282##       ##STR283##       790  183 C.sub.3 H.sub.7       (n) Br H SCN H H H      ##STR284##       ##STR285##       790  184 C.sub.4 H.sub.9       (n) Br H SCN H H H      ##STR286##       ##STR287##       790

EXAMPLE 185

To a mixture of 250 g of glacial acetic acid and 50 g of acetic anhydride were added 40.2 g of a compound of formula: ##STR288## and 17.5 g of a compound of formula: ##STR289## and the mixture was heated at 100° to 105° C. for 4 hours while stirring. After completion of the reaction, the reaction mixture was cooled to room temperature. The reaction mixture was then poured into 1.5 liters of water containing 16.0 g of sodium perchlorate, and the mixture was stirred at room temperature for 8 hours. The thus precipitated crystals were collected by filtration and dried to obtain 53.0 g of a naphthostyril dye of the formula shown below as dark green crystals. A chloroform solution of the dye had a λ_(max) of 800 nm. ##STR290##

One gram of the naphthostyril dye as above obtained was dissolved in 50 g of dibromoethane, followed by filtration through a filter of 0.22 μm. The resulting solution (2 ml) was coated on a substrate of grooved PMMA disc in the same manner as in Example 2 to form a coating film having a thickness of 700 Å. The coated film had a λ_(max) of 820 nm with a broad peak width.

When a semiconductor laser beam having a center wavelength of 830 nm and a beam diameter of 1 μm was irradiated on the coated film at an output of 6 mW, clearly outlined pits having a width of about 1 μm and a pit length of about 2 μm were formed. The C/N ratio of the pits was 52 dB. The coated film exhibited satisfactory light resistance and resistance to reproducing light.

EXAMPLE 186

In the same manner as described in Example 185, a naphthostyril dye of the formula shown below was synthesized. A chloroform solution of the dye had a λ_(max) of 795 nm. ##STR291##

One gram of the naphthostyril dye as above prepared and 1.5 g of nitrocellulose ("RS-20" produced by Daicel Chemical Industries, Ltd.) were dissolved in 50 g of ethyl cellosolve, and the solution was filtered through a filter of 0.22 μm. 3 ml of the resulting solution was dropped on a substrate of polycarbonate resin disc having a diameter of 120 mm which had been grooved to a depth of 650 Å and a width of 0.7 μm and coated by a spinner at 1,500 rpm, followed by drying at 60° C. for 10 minutes. The coated film has a thickness of 700 Å as measured in the same manner as in Example 1. The coated film exhibited maximum absorption at 810 nm of wavelength with a broad peak width.

When a semiconductor laser beam having a center wavelength of 830 nm and a beam diameter of 1 μm was irradiated on the coated film at an output of 6 mW, clearly outlined pits having a width of about 1 μm and a pit length of about 2 μm were formed. The thus formed recording layer had a C/N ratio of 51 dB and exhibited satisfactory light resistance and resistance to reproducing light.

EXAMPLE 187

A naphthostyril dye of the formula shown below was synthesized in the same manner as in Example 3. A chloroform solution of the dye had a λ_(max) of 800 nm. ##STR292##

One gram of the naphtholactam dye as above prepared was dissolved in 50 g of dibromoethane, followed by filtration through a filter of 0.22 μm. 2 ml of the resulting solution was dropped on a substrate of PMMA disc having a diameter of 120 mm which had been grooved to a depth of 700 Å and a width of 0.7 μm and coated by a spinner at 650 rpm, followed by drying at 60° C. for 10 minutes. The film thickness was 800 Å as measured in the same manner as in Example 1. The coated film had a λ_(max) of 820 nm with a broad peak width.

When a semiconductor laser beam having a center wavelength of 830 nm and a beam diameter of 1 μm was irradiated on the coated film at an output of 6 mW, clearly outlined pits having a width of about 1 μm and a pit length of about 2 μm were formed. The recording layer thus formed had a C/N ratio of 51 dB and exhibited satisfactory light resistance and resistance to reproducing light.

EXAMPLES 188 TO 278

In the same manner as in Example 185, naphthostyril dyes shown in Table 3 were synthesized. The wavelength of the absorption maximum of each of the resulting dyes in its chloroform solution was as shown in Table 3.

Each of the dyes was coated on a substrate of grooved PMMA disc in the same manner as in Example 185 to form a recording layer. When a semiconductor laser beam having a center wavelength of 830 nm was irradiated on the recording layer, clearly outlined pits were formed. The recording layer had a high reflectance, high sensitivity, and an excellent C/N ratio and exhibited satisfactory light resistance and resistance to reproduced light.

    TABLE 3       Naphtholactam Dye       ##STR293##                  λ max Example          (in CHCl.sub.3) No. R A.sup.1      A.sup.2 A.sup.3 B.sup.1 B.sup.2 B.sup.3 K Z.sup.- (nm)                   188 C.sub.2       H.sub.5 H H Br H H H      ##STR294##       ClO.sub.4.sup. - 805       189 " " " " " " "      ##STR295##       " 810       190 " " " " " " "      ##STR296##       " 807       191 " " " " " " "      ##STR297##       " 807       192 " " " " " " "      ##STR298##       " 800       193 " " " " " " "      ##STR299##       " 800       194 " " " " " " "      ##STR300##       " 790       195 " " " " " " "      ##STR301##       " 800       196 " " " " " " "      ##STR302##       " 800       197 " " " " " " "      ##STR303##       " 785       198 " " " " " " "      ##STR304##       " 800       199 " " " " " " "      ##STR305##       " 800       200 " " " " " " "      ##STR306##       " 810       201 " " " " " " "      ##STR307##       " 790       202 " " " " " " "      ##STR308##       " 800       203 " " " " " " "      ##STR309##       " 800       204 " " " " " " "      ##STR310##       " 800       205 " " " " " " "      ##STR311##       " 800       206 " " " " " " "      ##STR312##       " 820       207 " " " " " " "      ##STR313##       " 820       208 " " " " " " "      ##STR314##       " 825       209 " " " " " " "      ##STR315##       " 870       210 " " " " " " "      ##STR316##       " 840       211 " " " " " " "      ##STR317##       " 780       212 " " " " " " "      ##STR318##       " 810       213 " " " " " " "      ##STR319##       " 800       214 " " " " " " "      ##STR320##       I.sup.- 800       215 " " " " " " "      ##STR321##       " 795       216 " " " " " " "      ##STR322##       Br.sup.- 810       217 " " " " " " "      ##STR323##       " 810       218 " " " " " " "      ##STR324##       " 830       219 " " " " " " "      ##STR325##       " 820       220 " " " " " " "      ##STR326##       " 815       221 " " " " " " "      ##STR327##       " 806       222 " " " " " " "      ##STR328##       " 840       223 " " " " " " "      ##STR329##       BF.sub.4.sup.- 835  224 C.sub.3 H.sub.7       (n) " " " " " "      ##STR330##       " 805  225 C.sub.5 H.sub.11 (n) " " " " " " " " 805       226      ##STR331##       " " " " " " " " 805       227      ##STR332##       " " " " " " " " 805  228 C.sub.2 H.sub.4 OCH.sub.3 " " " " " " " " 805      229 CH.sub.2 CH.sub.2 CH.sub.2 OCH.sub.3 " " " " " " " " 805  230       ##STR333##       " " " " " " "       ##STR334##       805       231      ##STR335##       " " " " " " " " 805  232 C.sub.2 H.sub.4 OC.sub.2 H.sub.4 OCH.sub.3 " "      " " " " " " 805 233 C.sub.2 H.sub.4 OC.sub.2 H.sub.4 OC.sub.2 H.sub.4      OCH.sub.3 " " " " " " " " 805 234 C.sub.2 H.sub.4 OCH.sub.2 CHCH.sub.2 "      " " " " " " " 805 235 CH.sub.2 CHCH.sub.2 " " " " " " " " 805  236       ##STR336##       " " " " " " " " 805  237 C.sub.2 H.sub.4 OCH.sub.2 CHCH.sub.2 " " " " "      " " ClO.sub.4.sup.- 805 238 C.sub.2 H.sub.4 OH " " " " " " " " 805 239      C.sub.2 H.sub.4 Cl " " " " " " " SCN.sup.- 810       240      ##STR337##       " " " " " " " " 805  241 C.sub.2 H.sub.4 CN " " " " " " " " 810 242 " "      " H " " " " " 800  243 C.sub.2 H.sub.4       CN " "      ##STR338##       " " " " " 820       244 " " " H " " "      ##STR339##       ClO.sub.4.sup.- 810       245 " " " " " " "      ##STR340##       " 810       246 H " " " " " "      ##STR341##       ##STR342##       800  247 C.sub.2       H.sub.5 " "      ##STR343##       " " "       ##STR344##       " 820       248 " " " Cl " " " "      ##STR345##       805       249 " Br " Br " " " "      ##STR346##       810  250 " H " OCH.sub.3 " " " " " 815 251 " " " NHCH.sub.3 " " " " "      820       252 " " " Br " " "      ##STR347##       ClO.sub.4.sup.- 840       253 " " " " " " "      ##STR348##       " 860       254 " " " " " " "      ##STR349##       " 840       255 " " " " " " "      ##STR350##       " 860       256 " " " " " " "      ##STR351##       " 860       257 " " " " " " "      ##STR352##       " 850       258 " " " " " " "      ##STR353##       " 800       259 " " " " " " "      ##STR354##       " 835       260 " " " " " " "      ##STR355##       " 855       261 " " " OH " " "      ##STR356##       " 835       262 " " " NH.sub.2 " " "      ##STR357##       " 860  263 " " " NHC.sub.2       H.sub.5 " " "      ##STR358##       " 865       264 " " " NHCOCH.sub.3 " " "      ##STR359##       " 835       265 " " "      ##STR360##       " " "       ##STR361##       " 820       266 " " " Br " " "      ##STR362##       " 830       267 " Br " " " " "      ##STR363##       " 860       268 " " " " Br " "      ##STR364##       " 830       269 "  " " " " " Br      ##STR365##       " 855       270 " " " CH.sub.3 " " "      ##STR366##       " 855  271 " " " C.sub.2 H.sub.5 " " C.sub.2       H.sub.5      ##STR367##       " 835       272 " H " H H " H      ##STR368##       " 820       273 " " " SCN " " "      ##STR369##       SCN.sup.- 828  274 C.sub.3 H.sub.7 (n) " " " " " " " " 828 275 " " " Br      " " " " " 825 276 C.sub.2 H.sub.5 " " " " " " " PF.sub.6.sup.- 825 277 "      " " " " " " " SiF.sub.6.sup.- 825 278 " " " " " " " " TiF.sub.6.sup.-      820

EXAMPLES 279 TO 365

In the same manner as described in Example 187, naphthostyril dyes shown in Table 4 were synthesized. Each of the resulting naphthostyril dyes was coated on a substrate of grooved PMMA disc in the same manner as in Example 187 to form a coated film. The wavelength of the maximum absorption of the coated film was shown in Table 4.

When a laser beam having a center wavelength of 830 nm was irradiated on the coated film, clear-outlined pits were formed. The coated film had a high reflectance, high sensitivity, and an excellent C/N ratio and exhibited satisfactory light resistance and resistance to reproducing light.

    TABLE 4       Naphtholactam Dye       ##STR370##                  λ.sub.max Ex-          (coat- am-          ing) ple             film No. R A.sup.1 A.sup.2 A.sup.3 B.sup.1 B.sup.2 B.sup.3 K      Z.sup.- (nm)                   279 C.sub.2       H.sub.5 H H Br H H H      ##STR371##       ##STR372##       825  280 C.sub.2       H.sub.5 H H Br H H H      ##STR373##       ##STR374##       830  281 C.sub.2       H.sub.5 H H Br H H H      ##STR375##       ##STR376##       827  282 C.sub.2       H.sub.5 H H Br H H H      ##STR377##       ##STR378##       827  283 C.sub.2       H.sub.5 H H Br H H H      ##STR379##       ##STR380##       815   284 C.sub.2       H.sub.5 H H Br H H H      ##STR381##       ##STR382##       815  285 C.sub.2       H.sub.5 H H Br H H H      ##STR383##       ##STR384##       810  286 C.sub.2       H.sub.5 H H Br H H H      ##STR385##       ##STR386##       815  287 C.sub.2       H.sub.5 H H Br H H H      ##STR387##       ##STR388##       815  288 C.sub.2       H.sub.5 H H Br H H H      ##STR389##       ##STR390##       800  289 C.sub.2       H.sub.5 H H Br H H H      ##STR391##       ##STR392##       815  290 C.sub.2       H.sub.5 H H Br H H H      ##STR393##       ##STR394##       815  291 C.sub.2       H.sub.5 H H Br H H H      ##STR395##       ##STR396##       825  292 C.sub.2       H.sub.5 H H Br H H H      ##STR397##       ##STR398##       805  293 C.sub.2       H.sub.5 H H Br H H H      ##STR399##       ##STR400##       815  294 C.sub.2       H.sub.5 H H Br H H H      ##STR401##       ##STR402##       815  295 C.sub.2       H.sub.5 H H Br H H H      ##STR403##       ##STR404##       815  296 C.sub.2       H.sub.5 H H Br H H H      ##STR405##       ##STR406##       820  297 C.sub.2       H.sub.5 H H Br H H H      ##STR407##       ##STR408##       835  298 C.sub.2       H.sub.5 H H Br H HH      ##STR409##       ##STR410##       835  299 C.sub.2       H.sub.5 H H Br HH H      ##STR411##       ##STR412##       840  300 C.sub.2       H.sub.5 H H Br H H H      ##STR413##       ##STR414##       870  301 C.sub.2       H.sub.5 H H  Br H H H      ##STR415##       ##STR416##       850  302 C.sub.2       H.sub.5 H H Br H H H      ##STR417##       ##STR418##       800  303 C.sub.2       H.sub.5 H H Br H H H      ##STR419##       ##STR420##       830  304 C.sub.2       H.sub.5 H H Br H H H      ##STR421##       ##STR422##       820  305 C.sub.2       H.sub.5 H H Br H H H      ##STR423##       ##STR424##       820       306 C.sub.2 H.sub.5 H H Br H H H      ##STR425##       ##STR426##       815  307 C.sub.2       H.sub.5 H H Br H H H      ##STR427##       ##STR428##       830  308 C.sub.2       H.sub.5 H H Br H H H      ##STR429##       ##STR430##       830  309 C.sub.2       H.sub.5 H H Br H H H      ##STR431##       ##STR432##       845  310 C.sub.2       H.sub.5 H H Br H H H      ##STR433##       ##STR434##       835   311 C.sub.2       H.sub.5 H H Br H H H      ##STR435##       ##STR436##       835  312 C.sub.2       H.sub.5 H H Br H H H      ##STR437##       ##STR438##       826  313 C.sub.2       H.sub.5 H H Br H H H      ##STR439##       ##STR440##       855  314 C.sub.2       H.sub.5 H H Br H H H      ##STR441##       ##STR442##       845  315 C.sub.3 H.sub.7       (n) H H Br H H H      ##STR443##       ##STR444##       825 316 C.sub.5 H.sub.11       (n) H H Br H H H      ##STR445##       ##STR446##       825       317      ##STR447##       H H Br H H H       ##STR448##       ##STR449##       825       318      ##STR450##       H H Br H H H       ##STR451##       ##STR452##       825  318 C.sub.2 H.sub.4       OCH.sub.3 H H Br H H H      ##STR453##       ##STR454##       825  320 CH.sub.2 CH.sub.2 CH.sub.2       OCH.sub.3 H H Br H H H      ##STR455##       ##STR456##       825       321      ##STR457##       HH Br H H H       ##STR458##       ##STR459##       820       322      ##STR460##       H H Br H H H       ##STR461##       ##STR462##       820  323 C.sub.2 H.sub.4 OC.sub.2 H.sub.4 OCH.sub.3 H H Br H H H       ##STR463##       ##STR464##       820  324C.sub.2 H.sub.4 OC.sub.2 H.sub.4 OC.sub.2 H.sub.4 OCH.sub.3 H H B      r H H H       ##STR465##       ##STR466##       825  325 C.sub.2 H.sub.4 OCH.sub.2       CHCH.sub.2 H H Br H H H      ##STR467##       ##STR468##       825  326 CH.sub.2       CHCH.sub.2 H H Br H H H      ##STR469##       ##STR470##       820       327      ##STR471##       H H Br H H H       ##STR472##       ##STR473##       825  328 C.sub.2 H.sub.4 OCH.sub.2       CHCH.sub.2 H H Br H H H      ##STR474##       ##STR475##       825  329 C.sub.2 H.sub.4       OH H H Br H H H      ##STR476##       ##STR477##       825  330 C.sub.2 H.sub.4       Cl H H Br H H  H      ##STR478##       ##STR479##       830       331      ##STR480##       H H Br H H H       ##STR481##       ##STR482##       825  332 C.sub.2 H.sub.4       CN H H Br H H H      ##STR483##       ##STR484##       830  333 C.sub.2 H.sub.4       CN H H H H H H      ##STR485##       ##STR486##       820  334 C.sub.2 H.sub.4       CN H H      ##STR487##       H H H       ##STR488##       ##STR489##       835  335 C.sub.2 H.sub.4       CN H H H H H H      ##STR490##       ##STR491##       830  336 C.sub.2 H.sub.4       CN H H H H H H      ##STR492##       ##STR493##       830  337 C.sub.2       H.sub.5 H H      ##STR494##       H H H       ##STR495##       ##STR496##       835  338 C.sub.2       H.sub.5 H H Cl H H H      ##STR497##       ##STR498##       815  339 C.sub.2       H.sub.5 Br H Br H H H      ##STR499##       ##STR500##       825  340 C.sub.2       H.sub.5 H H OCH.sub.3 H H H      ##STR501##       ##STR502##       835  341 C.sub.2       H.sub.5 H H NHCH.sub.3 H H H      ##STR503##       ##STR504##       835  342 C.sub.2       H.sub.5 H H Br H H H      ##STR505##       ##STR506##       860  343 C.sub.2       H.sub.5 H H Br H H H      ##STR507##       ##STR508##       875  344 C.sub.2       H.sub.5 H H Br H H H      ##STR509##       ##STR510##       855  345 C.sub.2       H.sub. 5 H H Br H H H      ##STR511##       ##STR512##       875  346 C.sub.2       H.sub.5 H H Br H HH      ##STR513##       ##STR514##       875  347 C.sub.2       H.sub.5 H H Br H H H      ##STR515##       ##STR516##       865  348 C.sub.2       H.sub.5 H H Br H H H      ##STR517##       ##STR518##       820  349 C.sub.2       H.sub.5 H H Br H H H      ##STR519##       ##STR520##       855  350 C.sub.2       H.sub.5 H H Br  H H H      ##STR521##       ##STR522##       870  351 C.sub.2       H.sub.5 H H OH H HH      ##STR523##       ##STR524##       850  352 C.sub.2       H.sub.5 H H NH.sub.2 H HH      ##STR525##       ##STR526##       875  353 C.sub.2 H.sub.5 H H NHC.sub.2       H.sub.5 H H H      ##STR527##       ##STR528##       875  354 C.sub.2       H.sub.5 H H NHCOCH.sub.3 H H H      ##STR529##       ##STR530##       855  355 C.sub.2       H.sub.5 H H      ##STR531##       H H H       ##STR532##       ##STR533##       825  356 C.sub.2       H.sub.5 H H Br H H H      ##STR534##       ##STR535##       838  357 C.sub.2       H.sub.5 Br H Br H H H      ##STR536##       ##STR537##       875  358 C.sub.2       H.sub.5 Br H Br Br H H      ##STR538##       ##STR539##       845  359 C.sub.2       H.sub.5 Br H Br Br H Br      ##STR540##       ##STR541##       860  360 C.sub.2       H.sub.5 Br H CH.sub.3 Br H Br      ##STR542##       ##STR543##       860  361 C.sub.2 H.sub.5 Br HC.sub.2 H.sub.5 Br H C.sub.2 H.sub.5       ##STR544##       ##STR545##       840  362 C.sub.2       H.sub.5 H H H H H H      ##STR546##       ##STR547##       830  363 C.sub.2       H.sub.5 H H SCN H H H      ##STR548##       ##STR549##       835  364 C.sub.3 H.sub.7       (n) H H SCN H H H      ##STR550##       ##STR551##       835  365 C.sub.4 H.sub.9       (n) H H SCN H H H      ##STR552##       ##STR553##       835

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. 

What is claimed is:
 1. An optical recording medium adapted to record information by irradiating said recording medium comprising a support having provided thereon a recording layer containing a dye, with a focused laser beam, said dye undergoing thermal changes to thereby make a partial difference in reflectance on the recording medium, and for reproducing the recorded information by reading the difference in reflectance, which comprises a naphthostyril dye represented by formula (I): ##STR554## wherein K represents a substituted or unsubstituted aromatic amine residue; R represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted allyl group; Z⁻ represents an anion; ring A represents a substituted or unsubstituted naphthalene ring; and m represents 1 or
 2. 2. An optical recording medium as in claim 1, wherein said naphthostyril dye is a compound represented by formula (II): ##STR555## wherein X and Y each represents a hydrogen atom, a halogen atom, an alkyl group, an acylamino group, or an alkoxy group; R¹ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted allyl group; R² and R³ each represents a hydrogen atom, a substituted or unsubstituted alkyl group having up to 20 carbon atoms, a substituted or unsubstituted aryl group, a substituted or unsubstituted allyl group, or a substituted or unsubstituted cycloalkyl group; R⁴ and R⁵ each represents a hydrogen atom, a halogen atom, a cyano group, a thiocyanate group, an alkyl group having up to 10 carbon atoms, an alkoxy group having up to 10 carbon atoms, an alkylamino group, an acylamino group, an amino group, or a hydroxyl group; Z⁻ represents an anion; and m represents 1 or
 2. 3. An optical recording medium as in claim 1, wherein said naphthostyril dye is a compound represented by formula (III): ##STR556## wherein X represents a hydrogen atom or a methyl group; R¹ represents an alkyl group having up to 8 carbon atoms, an alkoxyalkyl group, an allyloxyalkyl group, an allyl group, or a hydroxyalkyl group; R² and R³ each represents an alkyl group having up to 8 carbon atoms, an alkoxyalkyl group, an alkoxyalkoxyalkyl group, an allyloxyalkyl group, an allyl group, a hydroxyalkyl group, or a halogenoalkyl group; R⁴ represents a hydrogen atom, a halogen atom, or a thiocyanate group; Z⁻ represents an anion; and m represents 1 or
 2. 4. An optical recording medium as in claim 1, wherein the anion as represented by Z⁻ is I⁻, Br⁻, Cl⁻, ClO₄ ⁻, BF₄ ⁻, SCN⁻, PF₆ ⁻, SiF₆ ⁻, TiF₆ ⁻, ##STR557## wherein R⁶, which may be the same or different when multiple R⁶ s are substituted, represents a hydrogen atom, an alkyl group having up to 6 carbon atoms, a halogen atoms, or a dialkyl amino group; and n represents 0 or an integer of from 1 to
 3. 5. An optical recording medium as in claim 2, wherein the anion as represented by Z⁻ is I⁻, Br⁻, Cl⁻, ClO₄ ⁻, BF₄ ⁻, SCN⁻, PF₆ ⁻, SiF₆ ⁻, TiF₆ ⁻, ##STR558## wherein R⁶, which may be the same or different when multiple R⁶ s are substituted, represents a hydrogen atom, an alkyl group having up to 6 carbon atoms, a halogen atom, or a dialkylamino group; and n represents 0 ro an integer of from 1 to
 3. 6. An optical recording medium as in claim 3, wherein the anion as represented by Z⁻ is I⁻, Br⁻, Cl⁻, ClO₄ ⁻, BF₄ ⁻, SCN⁻, PF₆ ⁻, SiF₆ ⁻, TiF₆ ⁻, ##STR559## when R⁶, which may be the same or different when multiple R⁶ s are substituted, represents a hydrogen atom, an alkyl group having up to 6 carbon atoms, a halogen atom, or a dialkylamino group; and n represents 0 or an integer of from 1 to
 3. 7. An optical recording medium as in claim 3, wherein R¹ is an alkyl group having up to 5 carbon atoms, an alkyl group having up to 5 carbon atoms which is substituted with an alkoxy group having up to 4 carbon atoms, an allyloxy group, or a hydroxyl group, or an allyl group.
 8. An optical recording medium as in claim 3, wherein R² and R³ each is an alkyl group having up to 8 carbon atoms, an alkyl group having up to 8 carbon atoms which is substituted with an alkoxy group having up to 4 carbon atoms, an alkoxyalkoxy group having up to 4 carbon atoms, an allyloxy group, a hydroxyl group, or a halogen atom, or an allyl group.
 9. An optical recording medium as in claim 3, wherein R⁴ is a hydrogen atom, a chlorine atom, a bromine atom, or a thiocyanato group.
 10. An optical recording medium as in claim 1, wherein Z⁻ is I⁻, Br⁻, Cl⁻, ClO₄ ⁻, BF₄ ⁻, SCN⁻, PF₆ ⁻, SiF₆ ⁻ or TiF₆ ⁻.
 11. An optical recording medium as in claim 2, wherein Z⁻ is I⁻, Br⁻, Cl⁻, ClO₄ ⁻, BF₄ ⁻, SCN⁻, PF₆ ⁻, SiF₆ ⁻ or TiF₆ ⁻.
 12. An optical recording medium as in claim 3, wherein Z⁻ is I⁻, Br⁻, Cl⁻, ClO₄ ⁻, SCN⁻, PF₆ ⁻, SiF₆ ⁻ or TiF₆ ⁻.
 13. An optical recording medium as in claim 1, wherein Z⁻ is ##STR560## wherein R⁶ is a hydrogen atom, or an alkyl group having up to 4 carbon atoms.
 14. An optical recording medium as in claim 2, wherein Z⁻ is ##STR561## wherein R⁶ is a hydrogen atom, or an alkyl group having up to 4 carbon atoms.
 15. An optical recording medium as in claim 3, wherein Z⁻ is ##STR562## wherein R⁶ is a hydrogen atom, or an alkyl group having up to 4 carbon atoms.
 16. An optical recording medium as in claim 1, wherein Z⁻ is ##STR563## wherein R⁶, which may be the same or different when multiple R⁶ s are substituted, represents a hydrogen atom, an alkyl group having up to 4 carbon atoms, a chlorine atom, or a dialkyl group having up to 4 carbon atoms; and n represents 0 or an integer of from 1 to
 3. 17. An optical recording medium as in claim 2, wherein Z⁻ is ##STR564## wherein R⁶, which may be the same or different when multiple R⁶ s are substituted, represents a hydrogen atom, an alkyl group having up to 4 carbon atoms, a chlorine atom, or a dialkyl group having up to 4 carbon atoms; and n represents 0 or an integer of from 1 to
 3. 18. An optical recording media as in claim 3, wherein Z⁻ is ##STR565## wherein R⁶, which may be the same or different when multiple R⁶ s are substituted, represents a hydrogen atom, an alkyl group having up to 4 carbon atoms, a chlorine atom, or a dialkyl group having up to 4 carbon atoms; and n represents 0 or an integer of from 1 to
 3. 19. An optical recording medium as in claim 16, wherein Z⁻ is ##STR566##
 20. An optical recording medium as in claim 17, wherein Z⁻ is ##STR567##
 21. An optical recording medium as in claim 18, wherein Z⁻ is ##STR568## 